1. Field of the Invention
The present invention generally relates to transistors and more particularly to a fin-type field effect transistor (FinFET) that has a front gate and a back gate.
2. Description of the Related Art
The back-gated complementary metal oxide semiconductor (CMOS) is a known means of achieving threshold voltage (Vt) control without the use of doping. Most structures that allow a back gate rely on burying a gate under an silicon-on-insulator (SOI) silicon layer. As a result, the front and back gates are very difficult to align to one another and to the source drain edges. Furthermore, the gate dielectric for the back gate is very limited by processes that construct such a structure to high-temperature materials such as silicon dioxide. It is desirable for the back gate to also be made of a low resistivity material such as tungsten, which makes for fairly thick values of back gate dielectric for good integrity electrically.